The allegedly alternative theories of Phyletic Gradualism and Punctuated Equilibria are examined as regards the nature of their differences. The explanatory value of both models is determined by establishing their actual connection with reality. It is concluded that they are to be considered complementary rather than mutually exclusive at all levels of infraspecific, specific, and supraspecific evolution. So, in order to be described comprehensively, the pathways of evolution require at least two distinct models, each based on a discrete (...) range of real phenomena. [Phyletic Gradualism; Punctuated Equilibria; evolutionary theories; divergence models; additive speciation; microevolution; macroevolution; anagenesis.]. (shrink)

They are correct that punctuated equilibria apply to sexually reproducing organisms and that morphological evolutionary change is regarded as largely (if not exclusively) correlated with speciation events. However, they err in suggesting that we attribute stasis strictly to "developmental constraints," which represent only one of a set of possible mechanisms that we have suggested for the causes of stasis. Others include habitat tracking and the internal structure of species themselves [for example, (2)].

The allegedly alternative theories of Phyletic Gradualism and Punctuated Equilibria are examined as regards the nature of their differences. The explanatory value of both models is determined by establishing their actual connection with reality. It is concluded that they are to be considered complementary rather than mutually exclusive at all levels of infraspecific, specific, and supraspecific evolution. So, in order to be described comprehensively, the pathways of evolution require at least two distinct models, each based on a discrete (...) range of real phenomena. [Phyletic Gradualism; Punctuated Equilibria; evolutionary theories; divergence models; additive speciation; microevolution; macroevolution; anagenesis.]. (shrink)

Many attempts have been made at supporting either one of the allegedly complementary divergence models Phyletic Gradualism and Punctuated Equilibria by patterns found in specific fossil sequences. However, assessing each model's connection with reality via such “individual case histories” appears not to constitute a relevant approach. Instead, in order to correctly establish the possible merits of both concepts, the claims of each have to be verified against general evolutionary theory. This is being pointed out herein by analyzing cladogenesis (...) at the specific level as an example. [Phyletic Gradualism; Punctuated Equilibria; evolutionary theory; divergence models; case histories; additive speciation.]. (shrink)

Evolution is frequently concentrated in bursts of rapid morphological change and speciation followed by long‐term stasis. We propose that this pattern of punctuated equilibria results from an evolutionary tug‐of‐war between host genomes and transposable elements (TEs) mediated through the epigenome. According to this hypothesis, epigenetic regulatory mechanisms (RNA interference, DNA methylation and histone modifications) maintain stasis by suppressing TE mobilization. However, physiological stress, induced by climate change or invasion of new habitats, disrupts epigenetic regulation and unleashes TEs. With (...) their capacity to drive non‐adaptive host evolution, mobilized TEs can restructure the genome and displace populations from adaptive peaks, thus providing an escape from stasis and generating genetic innovations required for rapid diversification. This “epi‐transposon hypothesis” can not only explain macroevolutionary tempo and mode, but may also resolve other long‐standing controversies, such as Wright's shifting balance theory, Mayr's peripheral isolates model, and McClintock's view of genome restructuring as an adaptive response to challenge. (shrink)

Many attempts have been made at supporting either one of the allegedly complementary divergence models Phyletic Gradualism and Punctuated Equilibria by patterns found in specific fossil sequences. However, assessing each model's connection with reality via such “individual case histories” appears not to constitute a relevant approach. Instead, in order to correctly establish the possible merits of both concepts, the claims of each have to be verified against general evolutionary theory. This is being pointed out herein by analyzing cladogenesis (...) at the specific level as an example. [Phyletic Gradualism; Punctuated Equilibria; evolutionary theory; divergence models; case histories; additive speciation.]. (shrink)

Several paleontologists have recently challenged the explanatory adequacy of the modern synthetic theory of evolution. Their position is that, contrary to the prevailing view that evolutionary change is gradual, the fossil record manifests long periods of species stasis (equilibrium) punctuated by periods of rapid species formation. And, they argue, this punctuated equilibria pattern challenges the gradualist, adaptationist and extrapolationist assumptions of the modern synthetic theory of evolution and supports a hierarchical, non-extrapolationist (non-reductionist) view of evolution. In this (...) paper I argue that the challenge rests on an inadequate characterization of the modern synthetic theory and that, even accepting punctuated equilibria and an irreducible evolutionary hierarchy, the modern synthetic theory is adequate to explain evolutionary change at all levels of the hierarchy. (shrink)

Several paleontologists have recently challenged the explanatory adequacy of the modern synthetic theory of evolution. Their position is that, contrary to the prevailing view that evolutionary change is gradual, the fossil record manifests long periods of species stasis punctuated by periods of rapid species formation. And, they argue, this punctuated equilibria pattern challenges the gradualist, adaptationist and extrapolationist assumptions of the modern synthetic theory of evolution and supports a hierarchical, non-extrapolationist view of evolution. In this paper I (...) argue that the challenge rests on an inadequate characterization of the modern synthetic theory and that, even accepting punctuated equilibria and an irreducible evolutionary hierarchy, the modern synthetic theory is adequate to explain evolutionary change at all levels of the hierarchy. (shrink)

This article seeks to show how several rhetorical tools were used and, in fact, played a central role in the argumentation advanced by Niles Eldredge and Stephen Jay Gould in their 1972 seminal article on the theory of Punctuated Equilibria. It is analyzed how Eldredge and Gould proceeded through three steps that, sequentially integrated, made their argument compelling. It is shown how they made use of analogies, metaphors and other rhetorical tools. It is sustained that they began by (...) priming the reader to distrust the current interpretation of the fossil record offered by most paleontologists and then, in a second step, they used specific visual representations in order to suggest that the competitor theory was committed to the idea of an even and slow evolution at a constant rate, an image utilized by them as straw man. Finally, it is analyzed how, in their third step, Eldredge and Gould made use of several rhetorical arguments to present their theory as new for paleontology while, at the same time, placing it well inside the frame of the modern synthesis, and how they also managed to present their theory as more promising and capable of making predictions for future researches than the competitor theory. (shrink)

Weak links, in the form of inadequacies in both reasoning and supporting evidence, exist at several critical steps in the derivation of an hierarchical concept of evolution from punctuated equilibria. Punctuation itself is predicated on a distorted reading of phyletic change as phyletic gradualism, and of allopatric speciation as the instantaneous formation of unchanging typological taxa. The concept of punctuation is further confounded by the indescriminate employment of the same term to denote both a causal explanation for evolutionary (...) change and an outcome of substantiated evolutionary processes. Even when the intended usage for the term is specified, each denotation of punctuation entails respective drawbacks. As a causal explanation, punctuation clearly belongs to the class of quantum theories with all their attendant impedimenta, including special salsatory non-adaptive mechanisms of evolutionary change. Redefinition of punctuation as a pattern of morphologic change reduces it to one possible outcome of known microevolutioanry processes, thus obviating any need for an hierarchical explanation of macroevolution. While vacillation between usages has preserved the term in the literature, the end result of this obfuscation has been a circle of faulty reasoning in which the pattern of punctuation is invoked as its own proof. Widespread confusion concerning what constitutes an adequate test of punctuation is directly attributable to imprecision in both the original and revised formulations of the concept.The argument for species-level selection is based on the typological and philosphically flawed premise of species as individuals, and further requires the hypothesis of heritable emergent properties, for which empirical evidence is lacking. (shrink)

We extend recent information-theoretic phase transition approaches to evolutionary and cognitive process via the Rate Distortion and Joint Asymptotic Equipartition Theorems, in the circumstance of interaction with a highly structured environment. This suggests that learning plateaus in cognitive systems and punctuated equilibria in evolutionary process are formally analogous, even though evolution is not cognitive. Extending arguments by Adami et al. (2000), we argue that 'adaptation' is the process by which a distorted genetic image of a coherently structured environment (...) is imposed upon a species. (shrink)

First, a brief history is provided of Popper's views on the status of evolutionary biology as a science. The views of some prominent biologists are then canvassed on the matter of falsifiability and its relation to evolutionary biology. Following that, I argue that Popper's programme of falsifiability does indeed exclude evolutionary biology from within the circumference of genuine science, that Popper's programme is fundamentally incoherent, and that the correction of this incoherence results in a greatly expanded and much more realistic (...) concept of what is empirical, resulting in the inclusion of evolutionary biology. Finally, this expanded concept of empirical is applied to two particular problems in evolutionary biology — viz., the species problem and the debate over the theory of punctuated equilibria — and it is argued that both of them are still mainly metaphysical. (shrink)

This book is divided in two parts, the first of which shows how, beyond paleontology and systematics, macroevolutionary theories apply key insights from ecology and biogeography, developmental biology, biophysics, molecular phylogenetics, and even the sociocultural sciences to explain evolution in deep time. In the second part, the phenomenon of macroevolution is examined with the help of real life-history case studies on the evolution of eukaryotic sex, the formation of anatomical form and body-plans, extinction and speciation events of marine invertebrates, hominin (...) evolution and species conservation ethics. The book brings together leading experts, who explain pivotal concepts such as Punctuated Equilibria, Stasis, Developmental Constraints, Adaptive Radiations, Habitat Tracking, Turnovers, (Mass) Extinctions, Species Sorting, Major Transitions, Trends, and Hierarchies – key premises that allow macroevolutionary epistemic frameworks to transcend microevolutionary theories that focus on genetic variation, selection, migration and fitness. Along the way, the contributing authors review ongoing debates and current scientific challenges; detail new and fascinating scientific tools and techniques that allow us to cross the classic borders between disciplines; demonstrate how their theories make it possible to extend the Modern Synthesis; present guidelines on how the macroevolutionary field could be further developed; and provide a rich view of just how it was that life evolved across time and space. In short, this book is a must-read for active scholars and, because the technical aspects are fully explained, it is also accessible for non-specialists. Understanding evolution requires a solid grasp of above-population phenomena. Species are real biological individuals, and abiotic factors impact the future course of evolution. Beyond observation, when the explanation of macroevolution is the goal, we need both evidence and theory that enable us to explain and interpret how life evolves at the grand scale. (shrink)

Species are thought by many to be important units of evolution. In this paper, I argue against that view. My argument is based on an examination of the role of species in the synthetic theory of evolution. I argue that if one adopts a gradualist view of evolution, one cannot make sense of the claim that species are units in the minimal sense needed to claim that they are units of evolution, namely, that they exist as discrete entities over time. (...) My second argument is directed against an appeal to Eldredge and Gould's theory of punctuated equilibria to support the claim that species are units of evolution. If one adopts their view, it may be possible to identify discrete temporal entities that can plausibly be termed species, but there is no reason to claim that those entities are units of evolution. Thus, on two plausible interpretations of the role of natural selection in the process of evolution, species are of no special importance. I then consider some of the reasons why species have been thought to be important evolutionary units by many contemporary evolutionary biologists. Finally, I discuss briefly the implications of this conclusion for evolutionary biology. (shrink)

Notions of uniform and gradual evolution have been replaced in some circles by biological and paleontological models that postulate that periods of rapid change punctuate long periods of evolutionary stasis. This new theory, called punctuated equilibria (or PE for short), may have implications for paradigms in scholarly disciplines other than the sciences. Whereas old evolutionary models exerted great influence upon historians, sociologists, anthropologists, and students of religion for more than a century, the new model may provide heuristic paradigms (...) for research that correlate more adequately with the current observations of scholars. We therefore provide suggestions for deployment of this new scientific paradigm in history and anthropology. In particular, this model can explain the rise of the Israelite state and the religious ethos in the Hebrew Bible, two major concerns of today's socioscientific study of biblical materials. Thus the possibility of an overarching paradigm for the social sciences is entertained. (shrink)

The theory of Punctuated Equilibria challenges the neo‐Darwinian tenet that evolution is a uniform process. Recently, an article by Hunt1 has found that directional change during the evolution of a lineage is relatively small (occurring only in 5% of 250 analyzed traits). Of those traits that were shown to follow a trend, size was more likely to show gradual changes, whereas shape changes were more random. Here, we provide a short view of the nature of evolutionary trends, showing (...) that directional change within lineages and among clades provides valuable evolutionary information about the processes involved in their generation. BioEssays 30:521–525, 2008. © 2008 Wiley Periodicals, Inc. (shrink)

A common criticism of punctuated equilibria as an evolutionary theory is that it erects a straw man by characterizing the modern synthesis as being devoid of mechanisms that bring about rapid speciation and abrupt changes in morphology. Thompson supports this view and argues that the modern synthesis does not entail gradualism, all-pervasive adaptationism, or extrapolationism and that punctuationists have mischaracterized the theory on all these points; properly understood the synthetic theory is hierarchical and able to explain phenomena at (...) all levels of the hierarchy, thus rendering macroevolutionary theories, such as punctuated equilibria, unnecessary. I argue in this paper that Thompson's approach is overly dependent upon rational reconstruction in the style of the logical empiricists, and as such ignores important sociological and historical factors that when taken into account justify punctuational criticism of the synthetic theory. (shrink)

In the wake of the paleobiological revolution of the 1970s and 1980s, paleontologists continue to investigate far-reaching questions about how evolution works. Many of those questions have a philosophical dimension. How is macroevolution related to evolutionary changes within populations? Is evolutionary history contingent? How much can we know about the causes of evolutionary trends? How do paleontologists read the patterns in the fossil record to learn about the underlying evolutionary processes? Derek Turner explores these and other questions, introducing the reader (...) to exciting recent work in the philosophy of paleontology and to theoretical issues including punctuated equilibria and species selection. He also critically examines some of the major accomplishments and arguments of paleontologists of the last 40 years. (shrink)

An insider's provocative account of one of the most contentious debates in science today When Niles Eldredge and Stephen Jay Gould, two of the world's leading evolutionary theorists, proposed a bold new theory of evolution—the theory of "punctuated equilibria"—they stood the standard interpretation of Darwin on its head. They also ignited a furious debate about the true nature of evolution. On the one side are the geneticists. They contend that evolution proceeds slowly but surely, driven by competition among (...) organisms to transmit their genes from generation to generation. On the other are the paleontologists, like Eldredge and Gould, who show in the fossil record that in fact evolution proceeds only sporadically. Long periods of no change—equilibria—are "punctuated" by episodes of rapid evolutionary activity. According to the paleontologists, this pattern shows that evolution is driven far more by environmental forces than by genetic competition. How can the prevailing views on evolution be so different? In Reinventing Darwin, Niles Eldredge offers a spirited account of the dispute and an impressive case for the paleontologists' side of the story. With the mastery that only a leading contributor to the debate can provide, he charts the course of theory from Darwin's day to the present and explores the fundamental mysteries and crucial questions that underlie the current quarrels. Is evolution fired by a gentle and persistent motor and fueled by the survival instincts of "selfish genes"? Or does it proceed in fits and starts, as the fossil record seems to show? What is the role of environmental changes such as habitat destruction and of cataclysmic events like meteor impacts? Are most species inherently stable, changing only very little until they succumb to extinction? Or are species highly adaptable, changing all the time? Eldredge sorts through the major findings and interpretations and presents a lively introduction to the leading edge of evolutionary theory today. Reinventing Darwin offers a rare insider's view of the sometimes contentious, but always stimulating work of scientific inquiry. PRAISE FOR NILES ELDREDGE'S PREVIOUS BOOKS The Miner's Canary: Unraveling the Mysteries of Extinction "The Miner's Canary rings with integrity. The author takes care to present opposing views. Some readers, indeed, might view Mr. Eldredge as a little too self-effacing; he is, after all, one of the world's leading experts in his field."—The New York Times Book Review Fossils: The Evolution and Extinction of Species "... an important and informative book. It is also delightfully idiosyncratic. This is no scholarly treatise defending academic argument. It is an essay for everyone interested in the story of earthly life."—The Christian Science Monitor Life Pulse: Episodes from the Story of the Fossil Record "This is Earth history on a grand scale; those who enjoy the works of Stephen Jay Gould will appreciate Life Pulse."—Publishers Weekly. (shrink)

This chapter surveys the philosophical problems raised by the two Darwinian claims of the existence of a Tree of a life, and the explanatory power of natural selection. It explores the specificity of explanations by natural selection, emphasizing the high context-dependency of any process of selection. Some consequences are drawn about the difficulty of those explanations to fit a nomological model of explanation, and the irreducibility of their historic-narrative dimension. The paper introduces to the debates about units of selection, stating (...) the compelling force of genic selectionnism but highlighting some critiques. Then it addresses the limits of selectionist explanations : the compared status of selection, drift and phylogenetic inertia are investigated, and the debates over adaptationism are presented, with the aim of defining the varieties of adaptationisms as research programs. In order to assess the scope of natural selection, the chapter addresses weak and strong challenges to the Synthetic theory of evolution, both from paleontology (punctuated equilibria, Gould’s contingency thesis) and evolutionary theory of development. We finally sketch some consequences of evolutionary theory concerning philosophical questions about human nature, on the basis of the hypothesis of the universality of selectionist explanations: this part deals mostly with epistemology and psychology. (shrink)

Since formulating the theory of punctuated equilibria in 1972, a group of prominent evolutionary biologists, geneticists, and paleontologists have contributed towards a significant reinterpretation of the neo-Darwinian image of evolution that had consolidated during the second half of the twentieth century. We believe a research program, which we might define as "evolutionary pluralism" or "post-Darwinism," has been outlined, one that is centered on the discovery of the complexity and multiplicity of elements that work together to produce changes in (...) our evolutionary systems. We are talking about a three-dimensional multiplicity: a multiplicity of rhythms in evolution (i.e., the theory of punctuated equilibria); a multiplicity of evolutionary units and levels (i.e., the hierarchical theory of evolution); and a multiplicity of factors and causes in evolution (i.e., the concept of exaptation). Although the reductionistic and deterministic view of natural history interprets the intelligence of evolution as a panoptic and executory rationality, evolutionary pluralism, going back to the original flexibility of the Darwinian opus, sees in the intelligence of evolution an ingenious m tis, an imperfect but very creative, craftsmanlike cleverness. The new metaphors of change introduced by evolutionary pluralism and the consequent criticism of the adaptational paradigm offer some very interesting spin-offs for the study of evolutionary systems in widely differing fields, from theoretical economics to the cognitive sciences. I propose a particular hypothesis concerning the possibility and usefulness of expanding the concept of exaptation into a general theory of developmental processes, both in biology as well as in the cognitive sciences. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Structure, Change, and Survival: A Response To Winthrop-youngFranco Moretti (bio)Geoffrey Winthrop-Young’s is the sort of review article one dreams of: long, intelligent, and very generous. So, first of all, thanks. And thanks also for the clarity with which disagreements are expressed. In the same spirit, here is a brief response.The first area of disagreement comes early in the article, when Winthrop-Young claims that in the Atlas, “the here and (...) now of a specific location suffers something akin to the fate of a Barthesian myth: its specificity is subordinated to a signifying function as part of an established narrative sequence. But as Moretti chooses not to address the question of how this transformation is achieved, his discussion tends to gloss over the differences between geographical, literary, and imaginary locations” [7]. Frankly, I don’t think this is true. I often do exactly what Winthrop-Young demands, using a sequence of maps to clarify the successive steps by which a geographical space ends up supporting a specific narrative strucure: see the Austen maps that open the book, or the picaresque sequence in the first chapter, or the Balzac and Dickens maps in the second chapter—where I also address the issue in conceptual terms in a section entitled “Stories of the Third.” It’s true that I don’t do so in every case (as perhaps I should), and Winthrop-Young may of course disagree with the way I chart the transformation of space into narrative, but he cannot deny that I am doing so. The fact that those maps compose sequences of increasing complexity (as is particularly clear for Austen and Our Mutual Friend) proves precisely that I am indeed mapping a “transformation” of relatively simple beginnings into a complicated final structure. Incidentally, I do something similar in Modern Epic, where I describe how Joyce’s stream of consciousness “grows” from rather slim paragraphs to the plump ones we read now, or follow the slow rise of Ulysses’s polyphony. Again: my theses may be wrong—but they are an attempt to follow the step-by-step structuration of a text (or genre). This, after all, is the basic test of critical materialism: if we cannot describe the how and the why of the various steps, we are implicitly invoking “creativity” as an explanation for literary products. Which is a bit like invoking God. But on the futility of this, Winthrop-Young and I probably agree.The second disagreement regards the tempo of literary history: does morphological change occur in brief bursts separated by long periods of stasis (as in Eldredge and Gould’s punctuated equilibria)—or is it more evenly distributed across time? Here, Winthrop-Young claims [36, fn 5] that my attempt to see Schwarz’s account of Brazilian modernism and the genesis of magic realism as a single instance of punctuated equilibria is contradicted by historical evidence. He is right. Years ago, I adopted punctuated equilibria because it proved better than any rival theory at explaining the peculiar rapidity of many literary turning points (baroque drama; the rise of the British novel; the modernist season of European literature). From this initial conviction, I was (unconsciously) led to generalize, and to treat every case of major morphological change as an instance of punctuated equilibria. This was silly, and Winthrop-Young is right in criticizing me. However, he would probably agree that a single (or even a few) contrary [End Page 41] instances do not invalidate a theory in its entirety, and that what we most need is to know more about how literary change occurs. Only after such an empirical reconnaissance will the testing of theories be on a truly sound basis. Personally, I wouldn’t be surprised if we discovered that literary change can occur in more than one way, and that we need more than one theory to account for it; still, all I know of literary history suggests that punctuated equilibria will be the theory with greatest explanatory power.The last disagreement concerns literary selection: specifically, whether my view of it is indeed Darwinian, or whether I Lamarck-like “transform the concept of selection from the traditional passive filter... (shrink)

Published comments by American scientists on Darwin’s evolutionary theory are rather rare in the latter half of the 19th century. Clarence King, the founding director of the U.S. Geological Survey in 1879, and an experienced field geologist, focused on the relation between Darwin’s evolutionary concepts and the larger context of Hutton/Lyell’s uniformitarianism versus Cuvier’s catastrophism in his 1877 paper, “Catastrophism and Evolution.” King knew that the fossil record contains little or no data supporting Darwin’s vision of gradual evolutionary change. Instead, (...) using horse evolution seen in the rocks of the American West, the very example that by the 1920s had become the shining exemplar of gradual evolutionary change, King argued for catastrophic extinction and evolutionary replacement by “plastic” species that were able to survive in modified form as components of the succeeding biota. Though he could not see such change as involving natural selection, in this novel use of the term “plasticity,” there may well be adumbrations of modern evolutionary biology. King’s themes became muted as Americans began to embrace more fully Darwin’s work. But his version of catastrophism never entirely disappeared, especially in paleobiological circles. And it came back in more fully modern form with force beginning with the work of Norman D. Newell on mass extinctions in the mid-20th century—and with that of two of his students: Eldredge and Gould’s “Punctuated Equilibria.” This essay introduces King’s “Catastrophism and Evolution” for the journal’s “Classics in Biological Theory” collection; King’s article is available as supplementary material in the online version of this introduction. (shrink)

This collection of essays, written over the past fifteen years by one of the more intrepid defenders of current Darwinian theory, contains material that will be of interest both to historians and philosophers of science and, since Ruse writes well and in an accessible manner, to an even wider audience. A preliminary glance at the contents primes one to expect to be both engaged and provoked; one is not disappointed. The essays include historical speculation on some of the views of (...) Charles Darwin, a defence of human sociobiology and discussion of its feminist critique, punctuated equilibria theory, teleology in biology, extraterrestrial biology and moral theory, the plate tectonic revolution in geology, and the relationship between evolutionary theory and Christian ethics. (shrink)

This paper examines the way in which paleontologists used “popular books” to call for a broader “expanded synthesis” of evolutionary biology. Beginning in the 1970s, a group of influential paleontologists, including Stephen Jay Gould, Niles Eldredge, David Raup, Steven Stanley, and others, aggressively promoted a new theoretical, evolutionary approach to the fossil record as an important revision of the existing synthetic view of Darwinism. This work had a transformative effect within the discipline of paleontology. However, by the 1980s, paleontologists began (...) making their case to a wider audience, both within evolutionary biology, and to the general public. Many of their books—for example, Eldredge’s provocatively-titled Unfinished Synthesis—explicitly argued that the received synthetic view of Darwinian evolution was incomplete, and that paleontological contributions such as punctuated equilibria, the hierarchical model of macroevolution, and the study of mass extinction dynamics offered a substantial corrective to evolutionary theory. This paper argues that books—far from being “mere popularizations” of scientific ideas—played an important role in disciplinary debates surrounding evolutionary theory during the 1980s, and in particular that paleontologists like Gould and Eldredge self-consciously adopted the book format because of the importance of that genre in the history of evolutionary biology. (shrink)

In this paper, I analyse the transition from gradualism to punctualism. I try to respond to the following question: Is the transition in question connected with an increase or decrease of falsifiability? My answer to that question is that from the classical Popperian point of view theory of Punctuated Equilibria is a failure because it does not satisfy the Popperian criteria of progress in the development of science. Classical Darwinism and Neodarwinism have failed in that they predict a (...) number of transitional forms in the fossil record that have never been found. The Punctuated Equilibria theory predicts abrupt appearance of new species and a following stasis. But it is hardly any success, as far as explanatory power is concerned, because the theory in question does not predict really any new facts, it may, therefore, be viewed as an ad hoc proposal. Moreover, its claims are, I argue, unfalsifiable to all practical ends and purposes. (shrink)

Benton Stidd has defended the position that punctuationists are not wrong about the inadequacy of the synthetic theory of evolution for explaining evolution. The thrust of his defense is that arguments to the contrary by Thompson involve a rational reconstruction along logical empiricist lines, which is insensitive to historical and social forces in a way that the Kuhnian Weltanschauung view that he espouses is not. I argue in this paper that Stidd has entirely misunderstood my arguments, that the soundness of (...) my arguments does not depend on acceptance of logical empiricism , and that Stidd fails to establish that punctuated equilibria is a new "paradigm". (shrink)

Benton Stidd has defended the position that punctuationists are not wrong about the inadequacy of the synthetic theory of evolution for explaining evolution. The thrust of his defense is that arguments to the contrary by Thompson involve a rational reconstruction along logical empiricist lines, which is insensitive to historical and social forces in a way that the Kuhnian Weltanschauung view that he espouses is not. I argue in this paper that Stidd has entirely misunderstood my arguments, that the soundness of (...) my arguments does not depend on acceptance of logical empiricism, and that Stidd fails to establish that punctuated equilibria is a new "paradigm". (shrink)

Plusieurs aspects de l’histoire évolutive sont envisagés. Les grands événements font intervenir des facteurs externes qui jouent au hasard. Les grandes séries évolutives montrent des sélections directionnelles constantes, qui orientent les changements morphologiques. Les équilibres ponctués et leur forte réintroduction de hasards sont critiqués. L’histoire des mammifères montre des évolutions répétées dans de multiples lignées de caractères nouveaux, qui suggèrent des contraintes de développement. Les progrès récents en biologie du développement expliquent comment les variations phénotypiques sont délimitées, réduisant fortement le (...) nombre des chemins évolutifs possibles. Cette diminution de la part du hasard rend l’évolution plus compréhensible. Several aspects of evolutionary history are here taken into consideration. Great events call for external factors, which operate largely by chance. Long evolutionary series manifest directional selections that are constant, orienting morphological changes. Punctuated equilibria and their strong reintroduction of chance factors are criticized. The history of mammals evinces repeated evolutions within multiple lineages of new characters, which suggest developmental constraints. Recent advances in developmental biology explain how phenotypic variations are limited, reducing considerably the number of possible evolutionary paths. This diminution of the role of chance makes evolution more comprehensible. (shrink)

A review of the literature and ethnographic data from Australia, Canada, New Zealand, the United States, and the United Kingdom on the research ethics review process suggest that moral panics can become triggers for punctuated equilibrium in the review process at both the macro and microlevel, albeit with significantly different levels of magnitude and impact. These data suggest that neither the development of the ethics review process nor the process itself proceeds gradually, but both are characterized by periodic major (...) shifts evoked by particular events or situations that result in varying levels of moral panic. One way to deal with this moral panic is to increase the regulation of research and the depth or intensity of the scrutiny of applications under ethics review. Moral panics at the macrolevel influence those at the microlevel and, if the moral panic evoked at the local or microlevel is not satisfactorily resolved, it will evoke action at a higher level. Understanding the evolution of research ethics review processes from this perspective might help make actions by ethics committees and policy makers more understandable and help explain why attention to research ethics are heightened at particular points in time. It may also provide a basis for developing recommendations for adaptations to the ethics review process and policy at both the local and macrolevel. (shrink)

PUNCTUATED cquilibrium has finally obtained an unambiguous and incontrovertiblc majoxity—that is, our theory is now 21 ' years old. We also, with parental pride (and, therefore, potential..

This paper clarifies the usage of Albert Hirschman’s categories of market behaviour as of exit and voice in debates about workplace democracy by taking seriously his critique of the neoclassical analysis of competition. Pro-market liberals are generally hostile to the idea of workplace democracy and tend to favour top-down hierarchies as a way of organising labour. This hostility is generally inspired by the neoclassical analysis of exploitation and efficiency, which leads them to defend distributions achieved through exit-based competitive equilibria. (...) Following Hirschman, I propose to consider a hypothetical alternative: a democratic equilibrium, reached through the use of voice. I show that it would present the same appealing characteristics than its competitive counterpart while also accounting for the non-ideal conditions in which markets operate. Support for free markets should entail support for workplace democracy minimally understood as a strengthening of voice. (shrink)

Natural language contains many expressions with underspecified emotive content. This paper proposes a way to resolve such underspecification. Nonmonotonic inference over a knowledge base is used to derive an expected interpretation for emotive expressions in a particular context. This ‘normal’ meaning is then taken to influence the hearer’s expectations about probable interpretations, and, because of these probable interpretations, the decisions of the speaker about when use of underspecified emotive terms is appropriate.

The paper attempts to rationalize cooperation in the one-shot prisoners' dilemma (PD). It starts by introducing (and preliminarily investigating) a new kind of equilibrium (differing from Aumann's correlated equilibria) according to which the players' actions may be correlated (sect. 2). In PD the Pareto-optimal among these equilibria is joint cooperation. Since these equilibria seem to contradict causal preconceptions, the paper continues with a standard analysis of the causal structure of decision situations (sect. 3). The analysis then raises (...) to a reflexive point of view according to which the agent integrates his own present and future decision situations into the causal picture of his situation (sect. 4). This reflexive structure is first applied to the toxin puzzle and then to Newcomb's problem, showing a way to rationalize drinking the toxin and taking only one box with-out assuming causal mystery (sect. 5). The latter result is finally extended to a rationalization of cooperation in PD (sect. 6). (shrink)

Natural language contains many expressions with underspecified emotive content. This paper proposes a way to resolve such underspecification. Nonmonotonic inference over a knowledge base is used to derive an expected interpretation for emotive expressions in a particular context. This ‘normal’ meaning is then taken to influence the hearer’s expectations about probable interpretations, and, because of these probable interpretations, the decisions of the speaker about when use of underspecified emotive terms is appropriate.

The Rescorla–Wagner model has been a leading theory of animal causal induction for nearly 30 years, and human causal induction for the past 15 years. Recent theories 367) have provided alternative explanations of how people draw causal conclusions from covariational data. However, theoretical attempts to compare the Rescorla–Wagner model with more recent models have been hampered by the fact that the Rescorla–Wagner model is an algorithmic theory, while the more recent theories are all computational. This paper provides a detailed derivation (...) of the long-run behavior of the Rescorla– Wagner model under a wide range of parameters and experimental setups, so that the model can be compared with computational theories. It also shows that the model agrees with competing theories on a wider range of cases than had previously been thought. The paper concludes by showing how recently suggested modifications of the Rescorla–Wagner model impact the long-run behavior of the model. (shrink)

This commentary suggests that an equilibrium framework may be retained, in an evolutionary model such as Gintis's and with more satisfactory results, if rationality is relaxed in a slightly different way than he proposes: that is, if decisions are assumed to be related to rewards probabilistically, rather than with certainty. This relaxed concept of rationality gives rise to probabilistic equilibria. (Published Online April 27 2007).

Different disciplines have analyzed binary choices to model collective behavior in human systems. Several situations in which social dilemma arise can be modeled as N-person prisoner’s dilemma games including homeland security, public goods, international political economy among others. The purpose of this study is to develop an analytical solution to the N-person prisoner’s dilemma game when boundedly rational agents interact in a population. Previous studies in the literature consider the case in which cooperators and defectors have the same learning factors. (...) We obtain an analytical equation to find equilibria in the N-person prisoner’s dilemma game in the general case when agents have different learning factors. We also introduce a more realistic approach where probability values are bounded between zero and one and therefore eliminates the possibility of infeasible probability values. Since no analytic solution can be derived in this case, agent based simulation is used to analyze the asymptotic behavior of the resulted dynamical system. (shrink)

Institutions are often regarded either as rules or as equilibria sustained by self-interested agents. I ask how these two theories can be combined. According to Philip Pettit’s _Virtual Control Theory_, they explain different things: rules explain why regularities persist; self-interest why they are resilient. Thus, his theory reconciles the two theories by adjusting their domains of application. However, the available evidence suggests that rules and self-interest often combine as sources of motivation. Because of this, it is better to integrate (...) the theories rather than to reconcile them. Inspired by Cristina Bicchieri’s theory of social norms, I incorporate the notion of rule-following into a game-theoretic account of institutions. According to the resulting _Rules-and-Equilibrium Theory_, institutions are rule- or norm-governed social practices. The theory does not only explain their persistence and resilience, but also their fragility, which provides another reason for preferring the proposed integration to Pettit’s reconciliation. (shrink)

This paper deals with the equilibria of games when the agents have multiple objectives and, therefore, their utilities cannot be represented by a single value, but by a vector containing the various dimensions of the utility. Our approach allows the incorporation of partial information about the preferences of the agents into the model, and permits the identification of the set of equilibria in accordance with this information. We also propose an additional conservative criterion which can be applied in (...) this framework in order to predict the results of interaction. The potential application of the theoretical results is shown with an analysis of a mixed oligopoly in which the agents value additional objectives other than their own benefit. These objectives are related to social welfare and to the profit of the industry. The flexibility of our approach provides a general theoretical framework for the analysis of a wide range of strategic economic models. (shrink)

Our scientific theories, like our cognitive structures in general, consist of propositions linked by evidential, explanatory, probabilistic, and logical connections. Those theoretical webs ‘impinge on the world at their edges,’ subject to a continuing barrage of incoming evidence. Our credences in the various elements of those structures change in response to that continuing barrage of evidence, as do the perceived connections between them. Here we model scientific theories as Bayesian nets, with credences at nodes and conditional links between them modelled (...) as conditional probabilities. We update those networks, in terms of both credences at nodes and conditional probabilities at links, through a temporal barrage of random incoming evidence. Robust patterns of punctuated equilibrium, suggestive of ‘normal science’ alternating with ‘paradigm shifts,’ emerge prominently in that change dynamics. The suggestion is that at least some of the phenomena at the core of the Kuhnian tradition are predictable in the typical dynamics of scientific theory change captured as Bayesian nets under even a random evidence barrage. (shrink)

In studies of multi-agent interaction, especially in game theory, the notion of equilibrium often plays a prominent role. A typical scenario for the belief merging problem is one in which several agents pool their beliefs together to form a consistent "group" picture of the world. The aim of this paper is to define and study new notions of equilibria in belief merging. To do so, we assume the agents arrive at consistency via the use of a social belief removal (...) function, in which each agent, using his own individual removal function, removes some belief from his stock of beliefs. We examine several notions of equilibria in this setting, assuming a general framework for individual belief removal due to Booth et al. We look at their inter-relations as well as prove their existence or otherwise. We also show how our equilibria can be seen as a generalisation of the idea of taking maximal consistent subsets of agents. (shrink)

This paper introduces a new equilibrium concept for normal form games called dependency equilibrium; it is defined, exemplified, and compared with Nash and correlated equilibria in Sections 2–4. Its philosophical motive is to rationalize cooperation in the one shot prisoners' dilemma. A brief discussion of its meaningfulness in Section 5 concludes the paper. †To contact the author, please write to: Department of Philosophy, University of Konstanz, 78457 Konstanz, Germany; e-mail: [email protected].